Why was the RCC called the lutheran heretic?

Answer 1

The Roman Catholic Church labeled Martin Luther a "heretic" because he challenged key Church doctrines and practices, particularly the sale of indulgences and the belief in salvation through faith and good works. His 95 Theses, which criticized these practices, sparked the Protestant Reformation and fundamentally questioned the authority of the Pope and the Church. Luther's emphasis on scripture as the sole source of authority (sola scriptura) and his rejection of certain sacraments further solidified this designation. As a result, the RCC deemed him a heretic for promoting beliefs that contradicted established Catholic teachings.